DE-PS 16 73 107 discloses an apparatus for analyzing liquids in which the sample tubes are moved by means of a chain drive within the analyzer. For this purpose, the individual chain links are provided with holding means into which the sample tubes can be inserted. The chain extends between two sprokets. The axle of one of the sprockets carries a disk having four recesses that are uniformly distributed over its periphery. In order to move a sample tube from a first processing station to a second, the disk rotates through 90 degrees and thereby carries along a sample tube engaged by a recess.
The known apparatus is very complex, space-consuming and requires regular maintenance if it is to operate reliably.